Cache literal sync filter validation (#17186)
The sliding sync proxy (amongst other things) use literal json blobs as
filters, and repeatedly validating them takes a bunch of CPU.
2 files changed, 14 insertions, 1 deletions
diff --git a/changelog.d/17186.misc b/changelog.d/17186.misc
new file mode 100644
index 0000000000..358209d5a0
--- /dev/null
+++ b/changelog.d/17186.misc
@@ -0,0 +1 @@
+Cache literal sync filter validation for performance.
diff --git a/synapse/rest/client/sync.py b/synapse/rest/client/sync.py
index 2b103ca6a8..d19aaf0e22 100644
--- a/synapse/rest/client/sync.py
+++ b/synapse/rest/client/sync.py
@@ -47,6 +47,7 @@ from synapse.http.site import SynapseRequest
from synapse.logging.opentracing import trace_with_opname
from synapse.types import JsonDict, Requester, StreamToken
from synapse.util import json_decoder
+from synapse.util.caches.lrucache import LruCache
from ._base import client_patterns, set_timeline_upper_limit
@@ -110,6 +111,11 @@ class SyncRestServlet(RestServlet):
self._msc2654_enabled = hs.config.experimental.msc2654_enabled
self._msc3773_enabled = hs.config.experimental.msc3773_enabled
+ self._json_filter_cache: LruCache[str, bool] = LruCache(
+ max_size=1000,
+ cache_name="sync_valid_filter",
+ )
+
async def on_GET(self, request: SynapseRequest) -> Tuple[int, JsonDict]:
# This will always be set by the time Twisted calls us.
assert request.args is not None
@@ -177,7 +183,13 @@ class SyncRestServlet(RestServlet):
filter_object = json_decoder.decode(filter_id)
except Exception:
raise SynapseError(400, "Invalid filter JSON", errcode=Codes.NOT_JSON)
- self.filtering.check_valid_filter(filter_object)
+
+ # We cache the validation, as this can get quite expensive if people use
+ # a literal json blob as a query param.
+ if not self._json_filter_cache.get(filter_id):
+ self.filtering.check_valid_filter(filter_object)
+ self._json_filter_cache[filter_id] = True
+
set_timeline_upper_limit(
filter_object, self.hs.config.server.filter_timeline_limit
)
|
